package common.server.utils;
import java.io.ByteArrayOutputStream;

public class Base64 {
	 private static char[] base64EncodeChars = { 'A', 'B', 'C', 'D', 
		     'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 
		     'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 
		     'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 
		     'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', 
		     '4', '5', '6', '7', '8', '9', '+', '/' };
		 
		   private static byte[] base64DecodeChars = { -1, -1, -1, -1, -1, 
		     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
		     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
		     -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 
		     60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 
		     10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, 
		     -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 
		     38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, 
		     -1, -1 };
		 
		   public static String encode(byte[] data)
		   {
		     StringBuffer sb = new StringBuffer();
		     int len = data.length;
		     int i = 0;
		 
		     while (i < len) {
		       int b1 = data[(i++)] & 0xFF;
		       if (i == len) {
		         sb.append(base64EncodeChars[(b1 >>> 2)]);
		         sb.append(base64EncodeChars[((b1 & 0x3) << 4)]);
		         sb.append("==");
		         break;
		       }
		       int b2 = data[(i++)] & 0xFF;
		       if (i == len) {
		         sb.append(base64EncodeChars[(b1 >>> 2)]);
		         sb.append(base64EncodeChars[
		           ((b1 & 0x3) << 4 | 
		           (b2 & 0xF0) >>> 4)]);
		         sb.append(base64EncodeChars[((b2 & 0xF) << 2)]);
		         sb.append("=");
		         break;
		       }
		       int b3 = data[(i++)] & 0xFF;
		       sb.append(base64EncodeChars[(b1 >>> 2)]);
		       sb.append(base64EncodeChars[
		         ((b1 & 0x3) << 4 | 
		         (b2 & 0xF0) >>> 4)]);
		       sb.append(base64EncodeChars[
		         ((b2 & 0xF) << 2 | 
		         (b3 & 0xC0) >>> 6)]);
		       sb.append(base64EncodeChars[(b3 & 0x3F)]);
		     }
		     return sb.toString();
		   }
		 
		   public static byte[] decode(String str)
		   {
		     byte[] data = str.getBytes();
		     int len = data.length;
		     ByteArrayOutputStream buf = new ByteArrayOutputStream(len);
		     int i = 0;
		 
		     while (i < len) {
		       int b1;
		       do
		         b1 = base64DecodeChars[data[(i++)]];
		       while ((i < len) && (b1 == -1));
		       if (b1 == -1) {
		         break;
		       }
		       int b2;
		       do
		         b2 = base64DecodeChars[data[(i++)]];
		       while ((i < len) && (b2 == -1));
		       if (b2 == -1) { break; }
		 
		       buf.write(b1 << 2 | (b2 & 0x30) >>> 4);
		       int b3;
		       do {
		         b3 = data[(i++)];
		         if (b3 == 61) {
		           return buf.toByteArray();
		         }
		         b3 = base64DecodeChars[b3];
		       }while ((i < len) && (b3 == -1));
		       if (b3 == -1) { break; }
		 
		       buf.write((b2 & 0xF) << 4 | (b3 & 0x3C) >>> 2);
		       int b4;
		       do {
		         b4 = data[(i++)];
		         if (b4 == 61) {
		           return buf.toByteArray();
		         }
		         b4 = base64DecodeChars[b4];
		       }while ((i < len) && (b4 == -1));
		       if (b4 == -1) {
		         break;
		       }
		       buf.write((b3 & 0x3) << 6 | b4);
		     }
		     return buf.toByteArray();
		   }
}
